Biological weapons are particularly attractive tools for terror because biological agents are available and easy to manufacture, small amounts are required to cause large-scale effects, and attacks can easily overwhelm existing medical resources. Reliable detection of biological agents in the field and in real time has proved to be challenging.
Toxins such as ricin, botulinum toxin or enterotoxin B are environmentally stable, can be mass-produced and do not need advanced technologies for production and dispersal. Clostridium botulinum neurotoxins are among the more deadly toxins and are listed as a National Institute of Allergy and Infectious Diseases (NIAID)—Category A agent for bioterrorism potential. According to Arnon et al. in “Botulinum Toxin as a Biological Weapon” (JAMA, Vol. 285, No. 8, pp. 1059-1070, 2001) and Greenfield et al. in “Microbiological, Biological, and Chemical Weapons of Warfare and Terrorism” (Am. J. Med. Sci., Vo. 323, No. 6, pp. 326-340, 2002), the lethal dose in unvaccinated humans is estimated at 1 ng/kg. Conventional methods of detection involve the use of high performance liquid chromatography (HPLC), mass spectrometry and colorimetric Enzyme-Linked ImmunoSorbent Assays (ELISAs); but these are impractical because such tests can only be carried out at centralized locations, and are too slow to be of practical value in the field. Another test for botulinum toxin detection is the ‘mouse assay,’ which relies on the death of mice as an indicator of toxin presence. Clearly, such a method is slow and impractical in the field.
A significant issue is the absence of a definite diagnostic method and the difficulty in differential diagnosis from other pathogens that would slow the response in case of a terror attack. This is a critical need that has to be met to have an effective response to terrorist attacks.
In addition to diagnostic methods for biological weapons applications, infectious diseases at hospitals and clinics require reliable and fast detection. Early detection of infectious diseases may be used to treat or prevent a disease or condition.
Methicillin Resistant Staphylococcus Aureus (MRSA) is a type of bacteria that is resistant to many antibiotics, thus fueling its spread in hospitals and healthcare facilities in which people have weakened immune systems. MRSA is very costly and time consuming to treat. In fact, the government estimates the annual costs of treating MRSA to be over four billion dollars. Due to the nature of the fast spreading bacteria, it is imperative to diagnose and begin treatment and isolation as soon as possible.
Unfortunately, the current “gold standard” for MRSA testing is culturing a sample in a lab, and although this is fairly reliable, it typically takes two to three days. Culturing is very time consuming and costs between $8 and $11 per culture. Therefore, an accurate, but faster, technique for detecting these bacteria is needed.